Sulphuric acid has been used to clear drains of many organic materials, including fats, hair, paper, cotton, tea, coffee grounds and tobacco, as well as some inorganic materials such as chalk, hard water salts, lime scale and iron salts. The properties of sulphuric acid which make it effective for drain cleaning include: (1) its high heat of dilution in contact with residual water in the drain which melts fats, greases and low melting compounds that otherwise act as clogging sites for other debris; (2) its reactivity with a wide range of function groups such as hydroxyl, carbonyls, esters, unsaturated bonds, rings and amino groups; and (3) its high dissociation constant that helps dissolve many organic and inorganic materials. Notable examples of use of sulphuric acid to clean drains are U.S. Pat. Nos. 3,538,008 to Ancel et al. and 4,096,871 to Vlahakis.
Polystyrene foam cups, foamed packing materials, wrapping sheets, toys or other items could contribute to drain blockage. Unfortunately, sulphuric acid will not affect polystyrene. Consequently, it is desirable to combine sulphuric acid with a polystyrene solvent in a single drain cleaning system. However, many polystyrene solvents are reactive with sulphuric acid and have not previously been employed together in a stable two-phase drain cleaning composition.
Previous drain cleaning compositions and processes that utilize hydrocarbon solvents include U.S. Pat. Nos. 3,553,145 and 3,553,146 to Butke et al., U.S. Pat. No. 3,666,670 to Gilbert et al., U.S. Pat. No. 3,576,751 to Noznick et al., and U.S. Pat. No. 3,060,125 to Sims. None of the disclosed compositions use halogenated hydrocarbon solvents specifically for dissolution of polystyrene.
It is an object of the present invention to form a two layer composition for diphase cleaning of a drain.
It is another object of the present invention to provide a method of cleaning a drain using a diphase composition of sulphuric acid and selected aromatic hydrocarbons.